Possible functions of CD169-positive sinus macrophages in lymph nodes in anti-tumor immune responses

A Physiologically Based Pharmacokinetic Model Relates the Subcutaneous Bioavailability of Monoclonal Antibodies to the Saturation of FcRn-Mediated Recycling in Injection-Site-Draining Lymph Nodes

The bioavailability of a monoclonal antibody (mAb) or another therapeutic protein after subcutaneous (SC) dosing is challenging to predict from first principles, even if the impact of injection site physiology and drug properties on mAb bioavailability is generally understood. We used a physiologically based pharmacokinetic model to predict pre-systemic clearance after SC administration mechanistically by incorporating the FcRn salvage pathway in antigen-presenting cells (APCs) in peripheral lymph nodes, draining the injection site. Clinically observed data of the removal rate of IgG from the arm as well as its plasma concentration after SC dosing were mostly predicted within the 95% confidence interval. The bioavailability of IgG was predicted to be 70%, which mechanistically relates to macropinocytosis in the draining lymph nodes and transient local dose-dependent partial saturation of the FcRn receptor in the APCs, resulting in higher catabolism and consequently less drug reaching the systemic circulation. The predicted free FcRn concentration was reduced to 40-45%, reaching the minimum 1-2 days after the SC administration of IgG, and returned to baseline after 8-12 days, depending on the site of injection. The model predicted the uptake into APCs, the binding affinity to FcRn, and the dose to be important factors impacting the bioavailability of a mAb.

Age-associated reduction of sinus macrophages in human mesenteric lymph nodes

There are numerous macrophages and dendritic cells in lymph nodes (LNs). Recent studies have highlighted that sinus macrophages (SMs) in LNs possess antigen-presenting capabilities and are related to anti-cancer immune responses. In this study, we assessed the distribution of SMs in mesenteric LNs removed during surgery for colorectal cancer. A marked reduction of SMs was noted in elderly patients, particularly those over 80 years old. We observed a disappearance of CD169-positive cells in LNs where SMs were reduced. In silico analysis of publicly available single-cell RNA sequencing data from LNs revealed that CD169-positive macrophages express numerous genes associated with antigen presentation and lymphocyte proliferation, similar to dendritic cells' functions. In conclusion, our study demonstrates that SMs, potentially crucial for immune activation, diminish in the LNs of elderly patients. This reduction of SMs may contribute to the immune dysfunction observed in the elderly.

PET/Computed Tomography Transformation of Oncology: Kidney and Urinary Tract Cancers

Renal cell carcinoma (RCC) and urothelial carcinoma (UC) are two of the most common genitourinary malignancies. 2-deoxy-2-[18F]fluoro-d-glucose (18F-FDG) can play an important role in the evaluation of patients with RCC and UC. In addition to the clinical utility of 18F-FDG PET to evaluate for metastatic RCC or UC, the shift in molecular imaging to focus on specific ligand-receptor interactions should provide novel diagnostic and therapeutic opportunities in genitourinary malignancies. In combination with the rise of artificial intelligence, our ability to derive imaging biomarkers that are associated with treatment selection, response assessment, and overall patient prognostication will only improve.

Anticancer immune reaction and lymph node sinus macrophages: a review from human and animal studies

Lymph nodes are secondary lymphoid organs localized throughout the body that typically appear as bean-like nodules. Numerous antigen-presenting cells, including dendritic cells and macrophages, that mediate host defense responses against pathogens, such as bacteria and viruses, reside within lymph nodes. To react to cancer cell-derived antigens in a variety of cancers, antigen-presenting cells induce cytotoxic T lymphocytes (CTLs). In relation to anticancer immune responses, macrophages in the lymph node sinus have been of particular interest because a number of studies involving both human specimens and animal models have reported that lymph node macrophages expressing CD169 play a key role in activating anticancer CTLs. Recent studies have indicated that dysfunction of lymph node macrophages potentially contributes to immune suppression in elderly patients and immunological "cold" tumors. Therefore, in anticancer therapy, the regulation of lymph node macrophages is a potentially promising approach.

Mechanisms and characteristics of subcapsular sinus macrophages in tumor immunity: a narrative review

Background and Objective

Lymph nodes constitute an integral component of the secondary lymphoid organs, housing a diverse population of macrophages. Macrophages exhibit heterogeneity in terms of localization, phenotype and ontogeny. Recent evidence has established that subcapsular sinus macrophages (SCSMs) are the initial cells exposed to antigens from afferent lymph vessels, playing a crucial role in the host immune response against invading pathogens and tumor cells. In order to summarize the role and mechanisms of SCSM in tumor immunity, this study systematically reviews research on SCSMs in tumor immunity.

Methods

A systematic search was conducted in PubMed and Web of Science to identify articles investigating clinical significance and mechanisms of SCSMs. Study eligibility was independently evaluated by two authors based on the assessment of titles, abstracts and full-texts.

Key Content and Findings

The narrative review included a total of 17 studies. Previous research consistently showed that a high level of SCSM in patients with various carcinomas is associated with a favorable long-term prognosis. SCSM acts as the front-line defender in antitumor activity, engaging in intricate communication with other immune cells. Moreover, SCSM could directly and indirectly modulate tumor immunity, and the integrity of SCSM layer is interrupted in disease status. Several studies explored the feasibility of targeting SCSM to activate immunity against tumors. However, the direct molecular interactions and alternation in signal pathway in the tumor immunity of SCSM are less well established in previous researches.

Conclusions

This narrative review underscores the critical role of SCSM in tumor immunity. Future studies should focus on the deeper mechanism underlying SCSMs and explore their clinical applications.

Expression of macrophage/dendritic cell-related molecules in lymph node sinus macrophages

The role of sinus macrophages (SMs) in anticancer immune responses has received considerable interest in recent years, but the types of molecules that are expressed in human SMs have not yet been clarified in detail. We therefore sought to identify dendritic cell (DC)- or macrophage-related molecules in SMs in human lymph nodes (LNs). SMs are strongly positive for Iba-1, CD163, CD169, and CD209. CD169 (clone SP216) reacted with almost all SMs, mainly in the cell surface membrane, while CD169 (clone HSn 7D2) reacted with a subpopulation of SMs, mainly in the cytoplasm, with a significant increase observed after IFN-α stimulation. The immunoreactivity of clone HSn 7D2 was markedly reduced after transfection with small interfering RNA against CD169, while that of clone SP216 was slightly reduced. The induction of CCL8 and CXCL10 messenger RNA (mRNA) expression by IFN-α was confirmed using cultured macrophages and RT-qPCR, but fluorescence in situ hybridization did not detect CCL8 and CXCL10 mRNA expression in SMs. Single-cell RNA sequence data of LNs indicated that the highest level of CXCL10 gene expression occurred in monocytes. In conclusion, we found that CD209, also known as DC-related molecule, was expressed in human SMs. The heterogeneity observed in CD169 reacted with cone HSn 7D2 and SP216 was potentially due to the modification of CD169 protein by IFN stimulation. Further, no expression of CXCL10 mRNA in SMs suggested that SMs might be resident macrophages.

Lymph node metastasis and tumor-educated immune tolerance: Potential therapeutic targets against distant metastasis

Lymph node metastasis has been shown to positively associated with the prognosis of many cancers. However, in clinical treatment, lymphadenectomy is not always successful, suggesting that immune cells in the tumor and sentinel lymph nodes still play a pivotal role in tumor immunosuppression. Recent studies had shown that tumors can tolerate immune cells through multiple strategies, including tumor-induced macrophage reprogramming, T cells inactivation, production of B cells pathogenic antibodies and activation of regulatory T cells to promote tumor colonization, growth, and metastasis in lymph nodes. We reviewed the bidirectional effect of immune cells on anti-tumor or promotion of cancer cell metastasis during lymph node metastasis, and the mechanisms by which malignant cancer cells modify immune cells to create a more favorable environment for the growth and survival of cancer cells. Research and treatment strategies focusing on the immune system in lymph nodes and potential immune targets in lymph node metastasis were also be discussed.

Multiscale deep learning framework captures systemic immune features in lymph nodes predictive of triple negative breast cancer outcome in large-scale studies

The suggestion that the systemic immune response in lymph nodes (LNs) conveys prognostic value for triple-negative breast cancer (TNBC) patients has not previously been investigated in large cohorts. We used a deep learning (DL) framework to quantify morphological features in haematoxylin and eosin-stained LNs on digitised whole slide images. From 345 breast cancer patients, 5,228 axillary LNs, cancer-free and involved, were assessed. Generalisable multiscale DL frameworks were developed to capture and quantify germinal centres (GCs) and sinuses. Cox regression proportional hazard models tested the association between smuLymphNet-captured GC and sinus quantifications and distant metastasis-free survival (DMFS). smuLymphNet achieved a Dice coefficient of 0.86 and 0.74 for capturing GCs and sinuses, respectively, and was comparable to an interpathologist Dice coefficient of 0.66 (GC) and 0.60 (sinus). smuLymphNet-captured sinuses were increased in LNs harbouring GCs (p < 0.001). smuLymphNet-captured GCs retained clinical relevance in LN-positive TNBC patients whose cancer-free LNs had on average ≥2 GCs, had longer DMFS (hazard ratio [HR] = 0.28, p = 0.02) and extended GCs' prognostic value to LN-negative TNBC patients (HR = 0.14, p = 0.002). Enlarged smuLymphNet-captured sinuses in involved LNs were associated with superior DMFS in LN-positive TNBC patients in a cohort from Guy's Hospital (multivariate HR = 0.39, p = 0.039) and with distant recurrence-free survival in 95 LN-positive TNBC patients of the Dutch-N4plus trial (HR = 0.44, p = 0.024). Heuristic scoring of subcapsular sinuses in LNs of LN-positive Tianjin TNBC patients (n = 85) cross-validated the association of enlarged sinuses with shorter DMFS (involved LNs: HR = 0.33, p = 0.029 and cancer-free LNs: HR = 0.21 p = 0.01). Morphological LN features reflective of cancer-associated responses are robustly quantifiable by smuLymphNet. Our findings further strengthen the value of assessment of LN properties beyond the detection of metastatic deposits for prognostication of TNBC patients. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Breast cancer associated CD169+ macrophages possess broad immunosuppressive functions but enhance antibody secretion by activated B cells

CD169⁺ resident macrophages in lymph nodes of breast cancer patients are for unknown reasons associated with a beneficial prognosis. This contrasts CD169⁺ macrophages present in primary breast tumors (CD169⁺ TAMs), that correlate with a worse prognosis. We recently showed that these CD169⁺ TAMs were associated with tertiary lymphoid structures (TLSs) and T_regs in breast cancer. Here, we show that CD169⁺ TAMs can be monocyte-derived and express a unique mediator profile characterized by type I IFNs, CXCL10, PGE₂ and inhibitory co-receptor expression pattern. The CD169⁺ monocyte-derived macrophages (CD169⁺ Mo-M) possessed an immunosuppressive function in vitro inhibiting NK, T and B cell proliferation, but enhanced antibody and IL6 secretion in activated B cells. Our findings indicate that CD169⁺ Mo-M in the primary breast tumor microenvironment are linked to both immunosuppression and TLS functions, with implications for future targeted Mo-M therapy.

Unraveling the Immune Microenvironment in Classic Hodgkin Lymphoma: Prognostic and Therapeutic Implications

Classic Hodgkin lymphoma (cHL) is a lymphoid neoplasm composed of rare neoplastic Hodgkin and Reed-Sternberg (HRS) cells surrounded by a reactive tumor microenvironment (TME) with suppressive properties against anti-tumor immunity. TME is mainly composed of T cells (CD4 helper, CD8 cytotoxic and regulatory) and tumor-associated macrophages (TAMs), but the impact of these cells on the natural course of the disease is not absolutely understood. TME contributes to the immune evasion of neoplastic HRS cells through the production of various cytokines and/or the aberrant expression of immune checkpoint molecules in ways that have not been fully understood yet. Herein, we present a comprehensive review of findings regarding the cellular components and the molecular features of the immune TME in cHL, its correlation with treatment response and prognosis, as well as the potential targeting of the TME with novel therapies. Among all cells, macrophages appear to be a most appealing target for immunomodulatory therapies, based on their functional plasticity and antitumor potency.

Novel Histopathological Biomarkers in Prostate Cancer: Implications and Perspectives

Prostate cancer (PCa) is the second most frequently diagnosed cancer in men. Despite the significant progress in cancer diagnosis and treatment over the last few years, the approach to disease detection and therapy still does not include histopathological biomarkers. The dissemination of PCa is strictly related to the creation of a premetastatic niche, which can be detected by altered levels of specific biomarkers. To date, the risk factors for biochemical recurrence include lymph node status, prostate-specific antigen (PSA), PSA density (PSAD), body mass index (BMI), pathological Gleason score, seminal vesicle invasion, extraprostatic extension, and intraductal carcinoma. In the future, biomarkers might represent another prognostic factor, as discussed in many studies. In this review, we focus on histopathological biomarkers (particularly CD169 macrophages, neuropilin-1, cofilin-1, interleukin-17, signal transducer and activator of transcription protein 3 (STAT3), LIM domain kinase 1 (LIMK1), CD15, AMACR, prostate-specific membrane antigen (PSMA), Appl1, Sortilin, Syndecan-1, and p63) and their potential application in decision making regarding the prognosis and treatment of PCa patients. We refer to studies that found a correlation between the levels of biomarkers and tumor characteristics as well as clinical outcomes. We also hypothesize about the potential use of histopathological markers as a target for novel immunotherapeutic drugs or targeted radionuclide therapy, which may be used as adjuvant therapy in the future.

CD169+ Macrophages Residing in the Draining Lymph Nodes and Infiltrating the Tumor Play Opposite Roles in the Pathogenesis of Bladder Cancer

Purpose

CD169⁺ macrophages are considered to enhance anti-tumor immunity by capturing lymph-borne dead tumor cells. The number of CD169⁺ macrophages in regional lymph nodes (RLNs) is positively correlated with prolonged cancer-free survival in various human cancers. However, a recent study argued against this dogma; that is, CD169⁺ macrophages infiltrating into the tumor were associated with poor prognosis in patients with breast cancer. To explain this discrepancy, we quantified the number of CD169⁺ macrophages located in the bladder tumor and RLNs of the same patients and examined their relationship with the 5-year survival rate.

Patients and Methods

Tumor and RLN specimens resected from 40 invasive bladder cancer patients (29 males and 11 females; median age, 70.7 years; range, 49-81 years) who underwent radical cystectomy were evaluated using immunostaining.

Results

The number of CD169⁺ macrophages in RLNs was associated with a good cancer prognosis, while CD169⁺ macrophages infiltrating the tumor strongly correlated with a higher incidence of lymphovascular invasion.

Conclusion

CD169⁺ macrophages play opposing roles in the induction of anti-tumor immunity based on their location in RLNs or tumors.

Naringenin potentiates anti-tumor immunity against oral cancer by inducing lymph node CD169-positive macrophage activation and cytotoxic T cell infiltration

The CD169⁺ macrophages in lymph nodes are implicated in cytotoxic T lymphocyte (CTL) activation and are associated with improved prognosis in several malignancies. Here, we investigated the significance of CD169⁺ macrophages in oral squamous cell carcinoma (OSCC). Further, we tested the anti-tumor effects of naringenin, which has been previously shown to activate CD169⁺ macrophages, in a murine OSCC model. Immunohistochemical analysis for CD169 and CD8 was performed on lymph node and primary tumor specimens from 89 patients with OSCC. We also evaluated the effects of naringenin on two murine OSCC models. Increased CD169⁺ macrophage counts in the regional lymph nodes correlated with favorable prognosis and CD8⁺ cell counts within tumor sites. Additionally, naringenin suppressed tumor growth in two murine OSCC models. The mRNA levels of CD169, interleukin (IL)-12, and C-X-C motif chemokine ligand 10 (CXCL10) in lymph nodes and CTL infiltration in tumors significantly increased following naringenin administration in tumor-bearing mice. These results suggest that CD169⁺ macrophages in lymph nodes are involved in T cell-mediated anti-tumor immunity and could be a prognostic marker for patients with OSCC. Moreover, naringenin is a new potential agent for CD169⁺ macrophage activation in OSCC treatment.

Siglecs as Therapeutic Targets in Cancer

Hypersialylation is a common post-translational modification of protein and lipids found on cancer cell surfaces, which participate in cell-cell interactions and in the regulation of immune responses. Sialic acids are a family of nine-carbon α-keto acids found at the outermost ends of glycans attached to cell surfaces. Given their locations on cell surfaces, tumor cells aberrantly overexpress sialic acids, which are recognized by Siglec receptors found on immune cells to mediate broad immunomodulatory signaling. Enhanced sialylation exposed on cancer cell surfaces is exemplified as "self-associated molecular pattern" (SAMP), which tricks Siglec receptors found on leukocytes to greatly down-regulate immune responsiveness, leading to tumor growth. In this review, we focused on all 15 human Siglecs (including Siglec XII), many of which still remain understudied. We also highlighted strategies that disrupt the course of Siglec-sialic acid interactions, such as antibody-based therapies and sialic acid mimetics leading to tumor cell depletion. Herein, we introduced the central roles of Siglecs in mediating pro-tumor immunity and discussed strategies that target these receptors, which could benefit improved cancer immunotherapy.

Regulation of prognosis-related Siglecs in the glioma microenvironment

PURPOSE

The anti-inflammatory environment of glioma reduces the efficacy of immunotherapies. Therefore, it is vital to transform the immunosuppressive microenvironment of glioma into a pro-inflammatory environment. Sialic acid-binding immunoglobulin-type lectins (Siglecs) can serve as immune checkpoint targets that enhance the anti-tumor immune response. However, the roles of Siglecs in the glioma microenvironment are unknown. This study was conducted to identify targets to inhibit the anti-inflammatory environment to improve therapeutic outcomes in patients with glioma.

METHODS

We analyzed the regulatory effect of prognosis-related Siglecs identified from data available in The Cancer Genome Atlas database (TCGA) and China Glioma Genome Atlas Data portal on the immunosuppressive microenvironment of glioma. The effects of prognosis-related Siglecs on the glioma microenvironment were investigated by determining the Pearson correlation coefficients of the Siglecs in transcriptome data from the TCGA database.

RESULTS

Siglec-1, -9, -10, and -14 were closely associated with the prognosis of patients with glioma. The expression of these four Siglecs was significantly increased in the high-risk group and positively correlated with anti-inflammatory cytokine levels in the glioma microenvironment.

CONCLUSION

Our study provides insights into the effects of prognosis-related Siglecs in glioma immunotherapy, suggesting that targeted prognosis-related Siglecs can modify the microenvironment of glioma and improve the sensitivity of patients with glioma to immunotherapy.

Anti-Cancer Immune Reaction and Lymph Node Macrophage; A Review from Human and Animal Studies

Lymph nodes are secondary lymphoid organs that appear as bean-like nodules usually <1 cm in size, and they are localized throughout the body. Many antigen-presenting cells such as dendritic cells and macrophages reside in lymph nodes, where they mediate host defense responses against pathogens such as viruses and bacteria. In cancers, antigen-presenting cells induce cytotoxic T lymphocytes (CTLs) to react to cancer cell-derived antigens. Macrophages located in the lymph node sinus are of particular interest in relation to anti-cancer immune responses because many studies using both human specimens and animal models have suggested that lymph node macrophages expressing CD169 play a key role in activating anti-cancer CTLs. The regulation of lymph node macrophages therefore represents a potentially promising novel approach in anti-cancer therapy.

Gene Expression Profiling of Lymph Node Sub-Capsular Sinus Macrophages in Cancer

Lymph nodes are key lymphoid organs collecting lymph fluid and migratory cells from the tissue area they survey. When cancerous cells arise within a tissue, the sentinel lymph node is the first immunological organ to mount an immune response. Sub-capsular sinus macrophages (SSMs) are specialized macrophages residing in the lymph nodes that play important roles as gatekeepers against particulate antigenic material. In the context of cancer, SSMs capture tumor-derived extracellular vesicles (tEVs), a form of particulate antigen released in high amounts by tumor cells. We and others have recently demonstrated that SSMs possess anti-tumor activity because in their absence tumors progress faster. A comprehensive profiling of SSMs represents an important first step to identify the cellular and molecular mechanisms responsible for SSM anti-tumor activity. Unfortunately, the isolation of SSMs for molecular analyses is very challenging. Here, we combined an optimized dissociation protocol, careful marker selection and stringent gating strategies to highly purify SSMs. We provide evidence of decreased T and B cell contamination, which allowed us to reveal the gene expression profile of this elusive macrophage subset. Squamous cell carcinomas induced an increase in the expression of Fc receptors, lysosomal and proteasomal enzymes in SSMs. Imaging of mouse and patient lymph nodes confirmed the presence of the top differentially expressed genes. These results suggest that SSMs respond to tumor formation by upregulating the machinery necessary for presentation of tumor particulate antigens to B cells.

SARS-CoV-2 Induces Lymphocytopenia by Promoting Inflammation and Decimates Secondary Lymphoid Organs

While lymphocytopenia is a common characteristic of coronavirus disease 2019 (COVID-19), the mechanisms responsible for this lymphocyte depletion are unclear. Here, we retrospectively reviewed the clinical and immunological data from 18 fatal COVID-19 cases, results showed that these patients had severe lymphocytopenia, together with high serum levels of inflammatory cytokines (IL-6, IL-8 and IL-10), and elevation of many other mediators in routine laboratory tests, including C-reactive protein, lactate dehydrogenase, α-hydroxybutyrate dehydrogenase and natriuretic peptide type B. The spleens and hilar lymph nodes (LNs) from six additional COVID-19 patients with post-mortem examinations were also collected, histopathologic detection showed that both organs manifested severe tissue damage and lymphocyte apoptosis in these six cases. In situ hybridization assays illustrated that SARS-CoV-2 viral RNA accumulates in these tissues, and transmission electronic microscopy confirmed that coronavirus-like particles were visible in the LNs. SARS-CoV-2 Spike and Nucleocapsid protein (NP) accumulated in the spleens and LNs, and the NP antigen restricted in angiotensin-converting enzyme 2 (ACE2) positive macrophages and dendritic cells (DCs). Furthermore, SARS-CoV-2 triggered the transcription of Il6, Il8 and Il1b genes in infected primary macrophages and DCs in vitro, and SARS-CoV-2-NP⁺ macrophages and DCs also manifested high levels of IL-6 and IL-1β, which might directly decimate human spleens and LNs and subsequently lead to lymphocytopenia in vivo. Collectively, these results demonstrated that SARS-CoV-2 induced lymphocytopenia by promoting systemic inflammation and direct neutralization in human spleen and LNs.

The role of macrophages in anti-tumor immune responses: pathological significance and potential as therapeutic targets

Malignant tumors comprise various types of normal cells and tumor cells, and are infiltrated by large numbers of immune cells, including macrophages. The results of numerous studies on the function and significance of intratumoral macrophages (tumor-associated macrophages) suggest that these macrophages generally enhance tumor progression rather than act as anti-tumor immune agents. Although much remains unknown, in this review, we attempt to describe the role of macrophages in the tumor microenvironment, and discuss their potential mechanisms on the recent immunotherapy.

CD169+ lymph node macrophages have protective functions in mouse breast cancer metastasis

Although the contribution of macrophages to metastasis is widely studied in primary tumors, the involvement of macrophages in tumor-draining lymph nodes (LNs) in this process is less clear. We find CD169⁺ macrophages as the predominant macrophage subtype in naive LNs, which undergo proliferative expansion in response to tumor stimuli. CD169⁺ LN macrophage depletion, using an anti-CSF-1R antibody or clodronate-loaded liposomes, leads to increased metastatic burden in two mouse breast cancer models. The expansion of CD169⁺ macrophages is tightly connected to B cell expansion in tumor-draining LNs, and B cell depletion abrogates the effect of CD169⁺ macrophage absence on metastasis, indicating that the CD169⁺ macrophage anti-metastatic effects require B cell presence. These results reveal a protective role of CD169⁺ LN macrophages in breast cancer metastasis and raise caution for the use of drugs aiming at the depletion of tumor-associated macrophages, which might simultaneously deplete macrophages in tumor-draining LNs.

CD169 Expression on Lymph Node Macrophages Predicts in Patients With Gastric Cancer

The induction of an anti-cancer immune responses is potentially associated with the efficacy of anti-cancer therapy. Recent studies have indicated that sinus macrophages in regional lymph nodes are involved in anti-cancer immune responses in the cancer microenvironment. In the present study, we investigated the correlation between lymphocyte infiltration in cancer tissues and macrophage activation in regional lymph nodes. We retrospectively identified 294 patients with gastric cancer who underwent surgery from 2008 to 2012. Using immunohistochemistry, we evaluated CD169-expression on CD68-positive macrophages, and the density of CD8-postive lymphocytes in tumor microenvironment. We statistically examined the correlation between CD169 and CD8 expression, and performed Cox regression analysis of potential prognostic factors, including CD169 and CD8 expression, for cancer-specific survival (CSS) in patients with total and advanced gastric cancer. CD169 overexpression in lymph node sinus macrophages (LySMs) was positively correlated to the density of CD8-positive lymphocytes in primary cancer tissues (R = 0.367, p < 0.001). A high density of CD8-positive T lymphocytes in the primary site and a high level of CD169 expression in LySMs were independently associated with greater CSS in patients with total and advanced gastric cancer (p < 0.05 for all). The expression on CD169 in LySMs is a predictor of a favorable clinical course in patients with gastric cancer, and might be useful for evaluating anti-cancer immune responses.

Liposomal Nanovaccine Containing α-Galactosylceramide and Ganglioside GM3 Stimulates Robust CD8+ T Cell Responses via CD169+ Macrophages and cDC1

Successful anti-cancer vaccines aim to prime and reinvigorate cytotoxic T cells and should therefore comprise a potent antigen and adjuvant. Antigen targeting to splenic CD169⁺ macrophages was shown to induce robust CD8⁺ T cell responses via antigen transfer to cDC1. Interestingly, CD169⁺ macrophages can also activate type I natural killer T-cells (NKT). NKT activation via ligands such as α-galactosylceramide (αGC) serve as natural adjuvants through dendritic cell activation. Here, we incorporated ganglioside GM3 and αGC in ovalbumin (OVA) protein-containing liposomes to achieve both CD169⁺ targeting and superior DC activation. The systemic delivery of GM3-αGC-OVA liposomes resulted in specific uptake by splenic CD169⁺ macrophages, stimulated strong IFNγ production by NKT and NK cells and coincided with the maturation of cDC1 and significant IL-12 production. Strikingly, superior induction of OVA-specific CD8⁺ T cells was detected after immunization with GM3-αGC-OVA liposomes. CD8⁺ T cell activation, but not B cell activation, was dependent on CD169⁺ macrophages and cDC1, while activation of NKT and NK cells were partially mediated by cDC1. In summary, GM3-αGC antigen-containing liposomes are a potent vaccination platform that promotes the interaction between different immune cell populations, resulting in strong adaptive immunity and therefore emerge as a promising anti-cancer vaccination strategy.

Functions of CD169 positive macrophages in human diseases (Review)

CD169⁺ macrophages are a unique type of macrophage subset that differ from M1 and M2 macrophages. CD169⁺ macrophages are present in multiple tissues and organs throughout the body and are primarily expressed in secondary lymphoid organs. These cells are primarily divided across three locations in secondary lymphoid organs: The metallophilic marginal zone of the spleen, the subcapsular sinus and the medulla of the lymph nodes. Due to their unique location distribution in vivo and the presence of the CD169 molecule on their surfaces, CD169⁺ macrophages are reported to serve important roles in several processes, such as phagocytosis, antigen presentation, immune tolerance, viral infection and inflammatory responses. At the same time, it has been reported that CD169⁺ macrophages may also serve an important role in anti-tumour immunity. The present review focuses on the research progress surrounding the function of CD169⁺ macrophages in a variety of diseases, such as viral infection, autoimmune diseases and tumours.

Inhibition of the CCL2 receptor, CCR2, enhances tumor response to immune checkpoint therapy

Immunotherapies targeting the PD-1/PD-L1 axis are now a mainstay in the clinical management of multiple cancer types, however, many tumors still fail to respond. CCL2 is highly expressed in various cancer types and has been shown to be associated with poor prognosis. Inhibition or blockade of the CCL2/CCR2 signaling axis has thus been an area of interest for cancer therapy. Here we show across multiple murine tumor and metastasis models that CCR2 antagonism in combination with anti-PD-1 therapy leads to sensitization and enhanced tumor response over anti-PD-1 monotherapy. We show that enhanced treatment response correlates with enhanced CD8+ T cell recruitment and activation and a concomitant decrease in CD4+ regulatory T cell. These results provide strong preclinical rationale for further clinical exploration of combining CCR2 antagonism with PD-1/PD-L1-directed immunotherapies across multiple tumor types especially given the availability of small molecule CCR2 inhibitors and antibodies.

Cancer treatment in the lymphatic system: A prospective targeting employing nanostructured systems

Cancer related to lymphangiogenesis has gained a great deal of attention in recent decades ever since specific markers of this intriguing system were discovered. Unlike the blood system, the lymphatic system has unique features that can advance cancer in future metastasis, or, conversely, can provide an opportunity to prevent or treat this disease that affects people worldwide. The aim of this review is to show the recent research of cancer treatment associated with the lymphatic system, considered one of the main gateways for disseminating metastatic cells to distant organs. Nanostructured systems based on theranostics and immunotherapies can offer several options for this complex disease. Precision targeting and accumulation of nanomaterials into the tumor sites and their elimination, or targeting the specific immune defense cells to promote optimal regression of cancer cells are highlighted in this paper. Moreover, therapies based on nanostructured systems through lymphatic systems may reduce the side effects and toxicity, avoid first pass hepatic metabolism, and improve patient recovery. We emphasize the general understanding of the association between the immune and lymphatic systems, their interaction with tumor cells, the mechanisms involved and the recent developments in several nanotechnology treatments related to this disease.

CD204-positive monocytes and macrophages ameliorate septic shock by suppressing proinflammatory cytokine production in mice

Sepsis is defined as a life-threatening multiorgan dysfunction caused by dysregulated inflammatory response to infection. It remains the primary cause of death from infection if not diagnosed and treated promptly. Therefore, a better understanding of the mechanism for resolving inflammation is needed. Monocytes and macrophages play a pivotal role not only in the induction but also in the suppression of inflammation. However, a tissue-resident macrophage subset that regulates a hyperinflammatory state during sepsis has not been explored. Here we show that CD204⁺ monocytes and/or macrophages rescued mice from endotoxin-induced septic shock. Serum and tissue proinflammatory cytokine levels were significantly upregulated in the absence of these cells. This study provided evidence that CD204⁺ monocytes and/or macrophages ameliorate septic shock by suppressing proinflammatory cytokine production.

Single-Cell Protein and RNA Expression Analysis of Mononuclear Phagocytes in Intestinal Mucosa and Mesenteric Lymph Nodes of Ulcerative Colitis and Crohn's Disease Patients

Inflammatory bowel diseases (IBDs), which include Crohn's disease (CD) and ulcerative colitis (UC), are driven by an abnormal immune response to commensal microbiota in genetically susceptible hosts. In addition to epithelial and stromal cells, innate and adaptive immune systems are both involved in IBD immunopathogenesis. Given the advances driven by single-cell technologies, we here reviewed the immune landscape and function of mononuclear phagocytes in inflamed non-lymphoid and lymphoid tissues of CD and UC patients. Immune cell profiling of IBD tissues using scRNA sequencing combined with multi-color cytometry analysis identifies unique clusters of monocyte-like cells, macrophages, and dendritic cells. These clusters reflect either distinct cell lineages (nature), or distinct or intermediate cell types with identical ontogeny, adapting their phenotype and function to the surrounding milieu (nurture and tissue imprinting). These advanced technologies will provide an unprecedented view of immune cell networks in health and disease, and thus may offer a personalized medicine approach to patients with IBD.

Transcriptomic Analysis and High-dimensional Phenotypic Mapping of Mononuclear Phagocytes in Mesenteric Lymph Nodes Reveal Differences Between Ulcerative Colitis and Crohn's Disease

BACKGROUND AND AIMS

Crohn's disease [CD] and ulcerative colitis [UC] are distinct forms of inflammatory bowel disease. Heterogeneity of HLA-DR+SIRPα + mononuclear phagocytes [MNPs], including macrophages [MΦ], monocyte-derived [Mono] cells, and dendritic cells [DCs], was reported in gut tissue but not yet investigated in mesenteric lymph nodes [MLNs] of IBD patients. We here compared the phenotype, function, and molecular profile of HLA-DR+SIRPα + MNPs in CD and UC MLNs.

METHODS

Cell distribution, morphology, immune function, and transcriptomic [bulk RNAseq] and high-dimensional protein expression profiles [CyTOF] of HLA-DR+SIRPα + MNPs were examined in MLNs of UC [n = 14], CD [n = 35], and non-IBD [n = 12] patients.

RESULTS

Elevated frequencies of CD14+CD64+CD163+ [Mono/MΦ-like] MNPs displaying monocyte/MΦ morphology and phagocytic function were a distinct feature of UC MLNs. In CD, the proportion of CD14-CD64-CD163- [DC-like] cells was augmented relative to Mono/MΦ-like cells; DC-like cells drove naïve T cell proliferation, Th1 polarisation, and Th17 TCM plasticity. Gene expression profile corroborated the nature of DC-like cells, best represented by BTLA, SERPINF, IGJ and, of Mono/MΦ-like cells, defined by CD163, MARCO, MAFB, CD300E, S100A9 expression. CyTOF analysis showed that CD123+ plasmacytoid cells predominated over conventional DCs in DC-like cells. Four CD163+ clusters were revealed in Mono/MΦ-like cells, two of which were enriched in MARCO-CD68dimHLA-DRdim monocyte-like cells and MARCOhiCD68hiHLA-DRhi Mɸ, whose proportion increased in UC relative to CD.

CONCLUSIONS

Defining the landscape of MNPs in MLNs provided evidence for expansion of CD163+ Mono/MΦ-like cells in UC only, highlighting a distinction between UC and CD, and thus the potential contribution of monocyte-like cells in driving colitis.

Vitamin E Scaffolds of pH-Responsive Lipid Nanoparticles as DNA Vaccines in Cancer and Protozoan Infection

DNA vaccinations are promising strategies for treating diseases that require cellular immunity (i.e., cancer and protozoan infection). Here, we report on the use of a liposomal nanocarrier (lipid nanoparticles (LNPs)) composed of an SS-cleavable and pH-activated lipidlike material (ssPalm) as an in vivo DNA vaccine. After subcutaneous administration, the LNPs containing an ssPalmE, an ssPalm with vitamin E scaffolds, elicited a higher gene expression activity in comparison with the other LNPs composed of the ssPalms with different hydrophobic scaffolds. Immunization with the ssPalmE-LNPs encapsulating plasmid DNA that encodes ovalbumin (OVA, a model tumor antigen) or profilin (TgPF, a potent antigen of Toxoplasma gondii) induced substantial antitumor or antiprotozoan effects, respectively. Flow cytometry analysis of the cells that had taken up the LNPs in draining lymph nodes (dLNs) showed that the ssPalmE-LNPs were largely taken up by macrophages and a small number of dendritic cells. We found that the transient deletion of CD169⁺ macrophages, a subpopulation of macrophages that play a key role in cancer immunity, unexpectedly enhanced the activity of the DNA vaccine. These data suggest that the ssPalmE-LNPs are effective DNA vaccine carriers, and a strategy for avoiding their being trapped by CD169⁺ macrophages will be a promising approach for developing next-generation DNA vaccines.

Maf expression in human macrophages and lymph node sinus macrophages in patients with esophageal cancer

The large Maf transcription factors are expressed in immune cells including macrophages and lymphocytes. To investigate the distribution of Maf expression in human organs, immunostaining for Maf was performed using sections of several human organs. High Maf expression was seen in the nucleus of macrophages in the gastrointestinal tract and lymph node sinus macrophages (LySMs). Then, we assessed whether Maf expression in LySMs was correlated with CD169 expression and the clinical prognosis in patients with esophageal cancer. Maf expression was associated with CD169 expression, but Maf expression in LySMs was not associated with the clinical course in patients with esophageal cancer. We determined which cytokines stimulate Maf expression using cultured macrophages. Immunocytochemistry showed that Maf expression was significantly elevated by interferon-γ. These results are the first report of Maf expression in human samples. Maf expression may be a marker for the macrophage population in humans.

α1-Acid Glycoprotein Has the Potential to Serve as a Biomimetic Drug Delivery Carrier for Anticancer Agents

Nanosize plasma proteins could be used as a biomimetic drug delivery system (DDS) for cancer treatment when loaded with anticancer drugs based on the fact that plasma proteins can serve as a source of nutrients for cancer cells. This prompted us to investigate the potential of α₁-acid glycoprotein (AGP) for this role because it is a nanosize plasma protein and binds a variety of anticancer agents. Pharmacokinetic analyses indicated that AGP is distributed more extensively in tumor tissue than human serum albumin, which was already established as a cancer DDS carrier. AGP is possibly being incorporated into tumor cells via endocytosis pathways. Moreover, a synthetic AGP-derived peptide which possesses a high ability to form an α-helix, as deduced from the primary structure of AGP, was also taken up by the tumor cells. AGP loaded with anticancer agents, such as paclitaxel or nitric oxide, efficiently induced tumor cell death. These results suggest that AGP has the potential to be a novel DDS carrier for anticancer agents.

Targeting Lymph Node Sinus Macrophages to Inhibit Lymph Node Metastasis

Lymph nodes are important peripheral immune organs in which numerous important immune responses occur. During the process of lymphatic metastasis, lymph nodes are also sites through which tumor cells must pass. Therefore, it is essential to develop a drug delivery system that can specifically transfer immunostimulatory medicine into lymph nodes to block lymphatic metastasis. Here, we developed a nucleic acid drug delivery system containing cationic agarose (C-agarose) and CpG oligodeoxynucleotides. C-agarose has a high affinity for Siglec-1 on the surface of lymph node sinus macrophages, which have a high specificity for targeting lymph nodes. Subcutaneous implantation of C-agarose+CpG gel caused the accumulation of CpG in the lymph node sinus macrophages and generated antitumor immune responses in the lymph node. C-agarose+CpG gel treatment decreased the metastasis size in the tumor-draining lymph node (TDLN) and lung metastatic nodules and suppressed tumor growth in both a mouse 4T1 breast cancer model and a B16F10 melanoma model. On this basis, this study proposes a nonsurgical invasive lymph node targeting immunotherapy concept that may provide a new approach for antitumor metastasis.

Harnessing the lymph node microenvironment

PURPOSE OF REVIEW

To evaluate role of the lymph node in immune regulation and tolerance in transplantation and recent advances in the delivery of antigen and immune modulatory signals to the lymph node.

RECENT FINDINGS

Lymph nodes are a primary site of immune cell priming, activation, and modulation, and changes within the lymph node microenvironment have the potential to induce specific regulation, suppression, and potentially tolerance. Antigen enters the lymph node either from tissues via lymphatics, from blood via high endothelial venules, or directly via injection. Here we review different techniques and materials to deliver antigen to the lymph node including microparticles or nanoparticles, ex-vivo antigen presenting cell manipulation, and use of receptor conjugation for specific intralymph node targeting locations.

SUMMARY

The promising results point to powerful techniques to harness the lymph node microenvironment and direct systemic immune regulation. The materials, techniques, and approaches suggest that translational and clinical trials in nonhuman primate and patients may soon be possible.

High CD169 expression in lymph node macrophages predicts a favorable clinical course in patients with esophageal cancer

Recent findings indicate CD169-positive lymph node sinus macrophages (LySMs) in the regional lymph nodes (RLNs) play an important role in anti-cancer immunity. In the present study, we investigated the correlation between CD169 expression in RLNs and clinicopathologic factors. Higher CD169 expression in LySMs was significantly associated with longer cancer-specific survival (CSS). The density of tumor-infiltrating lymphocytes (TILs) in the cancer nest and CD169 expression on LySMs were positively associated in patients who underwent pretreatment. As CD169 expression is thought to reflect a high interferon signature in RLNs, we tried to identify immunity-related genes that are up-regulated by interferon in macrophages as well as CD169. Indoleamine 2,3-dioxygenase (IDO1) was found to be elevated by interferon, and expression of IDO1 was tested using immunohistochemistry. IDO1 expression on LySMs was positively correlated with CD169 expression; however, there was no significant correlation between IDO1 and clinicopathologic factors. These results suggest that high expression of CD169 in LySMs reflects a high potential for anti-cancer immune responses in esophageal cancer patients and that monitoring CD169 expression would be useful for evaluating the potential of anti-cancer immune reactions.

Subcapsular Sinus Macrophages: The Seat of Innate and Adaptive Memory in Murine Lymph Nodes

Subcapsular sinus (SCS) macrophages are strategically positioned at the lymph-tissue interface in the lymph node to trap and present antigen to B cells. Recent murine data has shown that SCS macrophages also prevent the systemic spread of lymph-borne pathogens and are capable of activating a diverse range of innate effector and adaptive memory cells, including follicular memory T cells and memory B cells (B_mems), that are either pre-positioned or rapidly recruited to the subcapsular niche following infection and inflammation. Furthermore, B_mems are rapidly reactivated to differentiate into plasma cells in subcapsular proliferative foci (SPF). Thus, understanding how SCS macrophages coordinate both innate and adaptive memory responses in the subcapsular niche can provide new opportunities to bolster immunity against pathogens and cancer.

CD169 macrophages regulate immune responses toward particulate materials in the circulating fluid

Tissue macrophages comprise heterogeneous subsets that differ in localization, phenotype and ontogeny. They acquire tissue-specific phenotype in order to maintain normal tissue physiology. This review summarizes the current knowledge about the functions of CD169-positive macrophage subset residing in the lymphoid organs and intestinal tract. Strategically positioned at the interface between tissue and circulating fluid, CD169+ macrophages in the lymphoid organs capture blood- and lymph-borne particulate materials. Antigen information relayed by CD169+ macrophages to neighbouring immune cells is important for enhancement of antimicrobial and antitumour immunity as well as induction of tolerance. In the intestinal tract, CD169+ macrophages localize distantly from epithelial border. Following mucosal injury, they exacerbate inflammation by producing CCL8 that recruits inflammatory monocytes. As such, a better understanding of CD169+ macrophage phenotypes may enable the design of tissue-specific therapies for both immunological and non-immunological diseases.

LECTINS IN ANTI-CANCER STRATEGIES

The published during last few years data concerning communicative role of lectins (proteins and their complexes which recognize  carbohydrates, glycoconjugates and their patterns) in on-duty  supporting and increasing anticancer status of human immunity are  analyzed. Examples of lectin-(glycoconjugate pattern) strategies,  approaches and tactic variants in study and development of  anticancer treatments, principle variants of therapy, possible  vaccines in 35 cases of blood connected tumors (leukemia,  lymphomas, others), solid tumors (carcinomas, sarcoma, cancers of vaginal biotopes, prostate, bladder, colon, other intestinal  compartments, pancreas, liver, kidneys, others) and cancer cell lines  are described and systemized. The list of mostly used communicative lectins (pattern recognition receptors, their soluble forms, other  soluble lectins possessing specificities of importance) involving in key intercellular cascades and pathway co-functioning is presented. The  regulation of resulting expression of distinct active lectins (available and hetero/di/oligomeric forms) and their interaction to  adequate glycoconjugate patterns as well as influence distribution of  co-functioning lectins and antigens CD between populations and  subpopulations of antigen-presented cells (dendritic cells cDC, mDC,  moDC, pDC; macrophages M2 and M1), mucosal M-cells, NK-cells  play key role for choice and development of anticancer complex  procedures increasing innate and innate-coupled immune responses.  Prospects of (receptor lectin)-dependent intercellular  communications and targeting glycoconjugate constructions into  innate immunity cells for therapy of cancer and development of anticancer vaccines are evaluated and discussed.

Natural compounds that regulate lymph node sinus macrophages: Inducing an anti-tumor effect by regulating macrophage activation

Recent progress in anti-tumor therapy has revealed the significance of anti-tumor immune responses in tumor progression and clinical course in several kinds of malignant tumors. The draining lymph node is an important immune system component that contains a number of antigen-presenting cells, which induce rapid immune responses to foreign antigens. Current studies have shown that higher expression of CD169 on lymph node sinus macrophages is associated with the induction of anti-tumor immunity. In the present study, we searched for natural compounds that regulate the CD169-positive phenotype in macrophages to identify potential new anti-cancer agents targeting macrophage activation. Among 50 natural compounds, aculeatiside A, naringin, and onionin A significantly induced the CD169-positive phenotype in human monocyte-derived macrophages. These compounds also induced CD169 overexpression and secretion of inflammatory cytokines, including interleukin (IL)-1β and IL-12, in murine macrophages. Subcutaneous injection of aculeatiside A and naringin enhanced mRNA expression of IL-1β, IL12, and CD169 in regional lymph nodes in mice. These findings suggest aculeatiside A and naringin may enhance anti-tumor immune responses by inducing CD169-positive macrophages in lymph nodes.

CD169-positive sinus macrophages in the lymph nodes determine bladder cancer prognosis

CD169⁺ macrophages are suggested to play a pivotal role in establishing anti‐tumor immunity. They capture dead tumor cell‐associated antigens and transfer their information to lymphocsytes, including CD8⁺ T cells, which is important for successful tumor suppression. This study aimed to determine the prognostic significance of CD169⁺ macrophages residing in the tumor‐draining lymph nodes from cases of bladder cancer. In this retrospective study, 44 bladder cancer patients who received radical cystectomy were examined. The abundance of CD169⁺ macrophages in the regional lymph nodes and the number of CD8⁺ T cells in the primary tumor were investigated by immunohistochemistry. A CD169 score was calculated based on the intensity of CD169 staining and the proportion of CD169⁺ macrophages, and the scores were compared to the patients’ clinicopathological parameters. A high CD169 score was significantly associated with low T stage and with a high number of CD8⁺ T cells infiltrating into the tumor. The group with high CD169 expression had significantly longer cancer‐specific survival than the group with low CD169 expression (5‐year cancer‐specific survival rate: 83.3% vs 31.3%). In a multivariate analysis, the CD169 score was identified as a strong and independent favorable prognostic factor for cancer‐specific survival. Our findings suggest that CD169⁺ macrophages in the lymph nodes enhance anti‐tumor immunity by expanding CD8⁺ T cells in bladder cancer. The CD169 score may serve as a novel marker for the evaluation of bladder cancer prognosis.

Organoids with cancer stem cell-like properties secrete exosomes and HSP90 in a 3D nanoenvironment

Ability to form cellular aggregations such as tumorspheres and spheroids have been used as a morphological marker of malignant cancer cells and in particular cancer stem cells (CSC). However, the common definition of the types of cellular aggregation formed by cancer cells has not been available. We examined morphologies of 67 cell lines cultured on three dimensional morphology enhancing NanoCulture Plates (NCP) and classified the types of cellular aggregates that form. Among the 67 cell lines, 49 cell lines formed spheres or spheroids, 8 cell lines formed grape-like aggregation (GLA), 8 cell lines formed other types of aggregation, and 3 cell lines formed monolayer sheets. Seven GLA-forming cell lines were derived from adenocarcinoma among the 8 lines. A neuroendocrine adenocarcinoma cell line PC-3 formed asymmetric GLA with ductal structures on the NCPs and rapidly growing asymmetric tumors that metastasized to lymph nodes in immunocompromised mice. In contrast, another adenocarcinoma cell line DU-145 formed spheroids in vitro and spheroid-like tumors in vivo that did not metastasize to lymph nodes until day 50 after transplantation. Culture in the 3D nanoenvironment and in a defined stem cell medium enabled the neuroendocrine adenocarcinoma cells to form slowly growing large organoids that expressed multiple stem cell markers, neuroendocrine markers, intercellular adhesion molecules, and oncogenes in vitro. In contrast, the more commonly used 2D serum-contained environment reduced intercellular adhesion and induced mesenchymal transition and promoted rapid growth of the cells. In addition, the 3D stemness nanoenvironment promoted secretion of HSP90 and EpCAM-exosomes, a marker of CSC phenotype, from the neuroendocrine organoids. These findings indicate that the NCP-based 3D environment enables cells to form stem cell tumoroids with multipotency and model more accurately the in vivo tumor status at the levels of morphology and gene expression.

Reduced number of CD169+ macrophages in pre-metastatic regional lymph nodes is associated with subsequent metastatic disease in an animal model and with poor outcome in prostate cancer patients

BACKGROUND

Tumor-derived antigens are captured by CD169⁺ (SIGLEC1⁺ ) sinus macrophages in regional lymph nodes (LNs), and are presented to effector cells inducing an anti-tumor immune response. Reduced CD169 expression in pre-metastatic regional LNs is associated with subsequent metastatic disease and a poor outcome in several tumor types, but if this is the case in prostate cancer has not been explored.

METHODS

CD169 expression was measured with immunohistochemistry in metastasis-free regional LNs from 109 prostate cancer patients treated with prostatectomy (January 1996 to April 2002). Possible associations of CD169 expression with PSA-relapse, prostate cancer death, Gleason score, and other clinical data were assessed using Kaplan-Meier survival- and Cox regression analysis. In addition, the Dunning rat prostate tumor model was used to examine CD169 expression in pre-metastatic LNs draining either highly metastatic MatLyLu- or poorly metastatic AT1-tumors.

RESULTS

In patients with low CD169 immunostaining in metastasis-free regional LNs, 8 of the 27 patients died from prostate cancer compared with only three of the 82 patients with high immunostaining (P < 0.001). CD169 expression in regional LNs was not associated with PSA-relapse. Rats with highly metastatic tumors had decreased CD169 immunoreactivity in pre-metastatic regional LNs compared with rats with poorly metastatic tumors.

CONCLUSION

Low expression of CD169 in metastasis-free regional LNs indicates a reduced anti-tumor immune response. If verified in other studies, CD169 expression in regional LNs could, in combination with other factors, potentially be used as a marker of prostate cancer aggressiveness.

Optimum immunohistochemical procedures for analysis of macrophages in human and mouse formalin fixed paraffin-embedded tissue samples

Macrophages are closely related to various diseases and it is therefore important that the properties of macrophages are adequately evaluated in human diseases and mouse disease models. Immunohistochemistry (IHC) of formalin fixed paraffin-embedded (FFPE) samples is a very useful tool for examination of macrophages; however, an adequate IHC protocol is required for the examination of macrophage states. In this study, we assessed various antigen retrieval methods in order to devise the optimal protocols for staining of macrophages with a range of antibodies. Optimum combinations of primary antibodies and antigen retrieval protocols were determined; for example, heat treatment with ethylenediamine tetraacetic acid solution, pH 8.0, was the best procedure for IHC using mouse anti-Iba1 and human anti-CD11b, -CD163, -CD169, -CD204, and -CD206 antibodies. Moreover, we found that the immunoreactivity of sliced tissue sections decreased gradually over time in long term storage but that this immunoreactivity was preserved in storage at -80 °C in a deep freezer. The optimal IHC protocols and storage procedures that were determined in this study should be a useful tool for macrophage research.

Possible functions of CD169-positive sinus macrophages in lymph nodes in anti-tumor immune responses

The lymph node (LN) is an important immune system in which a number of antigen‐presenting cells are present that induce rapid immune responses to foreign antigens. While a great number of macrophages exist in lymph nodes, recent studies using animal models have shown that lymph node sinus macrophages are associated with the induction of anti‐tumor immunity, playing a significant role in host immune responses against tumor cells. In colorectal tumor, malignant melanoma, and endometrial tumor, it was shown that a high density of CD169‐positive macrophages in the LN sinus was a predictive factor for better clinical prognosis. The observations that the density of CD169‐positive macrophages in the LN sinus was positively associated with the density of infiltrating T or NK cells in tumor tissues, indicates the significance of CD169‐positive macrophages in anti‐tumor immune reactions of tumor patients. Moreover, antigen delivery targeting LN macrophages is also considered to be promising approach for vaccination. In this article, we have summarized the significance of CD169‐positive LN macrophages in anti‐tumor immunity.